Premium fuel needed????

16 replies to this topic
  • ronkrom

Posted March 06, 2007 - 03:55 PM


I recently did all the "free mods" for my 06' WR450 and am wondering if someone can tell me if premium fuel is still needed?


  • baja4lif3

Posted March 06, 2007 - 04:04 PM


Its best to run 91 premium in any bike taht is stock or not on race gas. Especially since it is a high-revving four stroke.

  • Seabass

Posted March 06, 2007 - 04:05 PM


Definately run 91 octane, race fuel would be a waste of money.

  • Tough Guy

Posted March 06, 2007 - 06:45 PM


My 07 has a sticker on the front fender that says it requires premium fuel...FWIW.


  • jim_wr250f

Posted March 06, 2007 - 11:26 PM


hmm in aust. our ordinary unleaded is 93octane premium is 95octane and there is ultimate98 available and a 100octane which has ethanol.

  • dangermouse007

Posted March 07, 2007 - 12:21 AM


99 oct over here ..

  • clark4131

Posted March 07, 2007 - 07:05 AM


The octane rating specified in the manual is the Research Octane Number, or RON. The manner in which the octane rating in the US is expressed is the Pump Octane Number, or PON, which is determined with the formula RON+MON/2. MON is short for Motor Octane Number which is always lower than the RON. Generally speaking, if you have a rating of 92 at the pump, you can be fairly certain that the gas has a RON of 95 or better. Here's a great article that explains it much better than I can, complete with graphs and charts :lol: :applause: ...SC

  • griffithds

Posted March 07, 2007 - 07:57 AM


Thanks for the article clark 4131. I've read a lot of fuel articles and some get very confusing. This one was simple, straight forward, and easy to remember.

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  • Gorby

Posted March 07, 2007 - 09:44 PM


I always run 91.

  • Jammer

Posted March 10, 2007 - 06:23 AM


None of the mods change the compression ratio. And, with the mods done, you're squeezing even MORE fuel into that little combustion chamber - probably need the premium more now than before.

  • AMG_Eric

Posted March 10, 2007 - 10:54 PM


i've run 87 and 89 in my uncorked 450 05 and havent noticed a difference.

  • C-P

Posted March 11, 2007 - 07:19 PM


There's some stuff going around MN about also using non-oxygenated fuel. BP is generally a good source.

  • dmwaterdog

Posted December 30, 2007 - 07:27 AM


I have a WR400F and have used almost exclusively 87 0ctane for years with no noticeable problems. I have listened for pinging, checked the plug for preignition damage and have detected no problems (it may even have the original plug). This bike is ridden hard both street (Sportmans Class fashion with street tires) and dirt and has definitely not been babied. It is one of the most versatile and durable bikes I have ridden with plenty of hours on it.:banghead:
Anyone one else have any actual experience running 87 Octane? Has anyone detected any detonation or preignition running lower grade fuels?

  • arcboy

Posted December 30, 2007 - 11:37 AM


Don't you get a bit more power out of race gas? I have read that it runs cooler and burns more efficent. Something running cooler and more efficient gives more power right?

I occasionally buy some 100 octane @ about $6/gallon. Mostly when I go trail riding.

Oh yeah it smells awesome :banghead:

  • Blackmax

Posted December 30, 2007 - 12:02 PM


What about octane boost in a can? Would that help?


Posted December 30, 2007 - 01:14 PM


I usually use 94 if the station I get it from is open if not I'll get the next highest rating.


  • clark4131

Posted December 30, 2007 - 07:01 PM


Don't you get a bit more power out of race gas? I have read that it runs cooler and burns more efficent. Something running cooler and more efficient gives more power right?

Higher octane does not necessarily translate into more power. The octane rating is a measure of how resistant gasoline is to the abnormal combustion phenomenon known as detonation (also known as knocking, pinging, spark knock, and other names). Higher octane is needed the higher your compression ratio. Higher octane in an engine that doesn't need it, actually produces less power. The same is true for an engine that needs it but doesn't get it, but then you get the added bonus of the detonation which can actually damage the cylinder. So, in order to get the most energy out of your bike based on the fuel, you need to determine what is the lowest octane fuel you can use without getting pinging...:banghead:


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